Adding some formatting instructions for contributing (#626)

* init adding of formatting instructions

* Update developers/contributing/index.qmd

Co-authored-by: Penelope Yong <penelopeysm@gmail.com>

* Update developers/contributing/index.qmd

Co-authored-by: Penelope Yong <penelopeysm@gmail.com>

* Update Manifest.toml

* okay i'll just do it

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Co-authored-by: AoifeHughes <aoife1hughes@gmail.com>
Co-authored-by: Penelope Yong <penelopeysm@gmail.com>
Co-authored-by: Markus Hauru <mhauru@turing.ac.uk>

Author: 4 people